Process for separating the rare earth elements by means of solvent extraction

Claim 1

A METHOD FOR THE SEPARATION OF AT LEAST ONE RARE EARTH ELEMENT FROM AT LEAST ONE OTHER RARE EARTH ELEMENT IN AN AQUEOUS SULFATE SOLUTION CONTAINING THE RARE EARTHS IN A CONCENTRATION OF ABOUT 0.005 TO 0.05 MOL PER LITER WHICH COMPRISES (1) ADDING TO SAID SOLUTION ABOUT 2 TO 10 GRAMS PER LITER OF THE SOLUTION OF A COMPLEXING AGENT SELECTED FROM THE GROUP CONSISTING OF ETHYLENEDIAMINE TETRAACETIC ACID, DIETHYLENETRIAMINE PENTAACETIC ACID, NITRILOTRIACETIC ACID, 1, 2-DIAMINOCYCLOHEXANE TETRAACETIC ACID, N-HYDROXYETHYLENEDIAMINE TRIACETIC ACID AND A-ISOBUTYRATE, AND (2) CONTACTING SAID AQUEOUS SOLUTION WITH AN AMINE FROM THE GROUP CONSISTING OF A MIXTURE OF PRIMARY AMINES FROM T-C12H25NH2 TO T-C14H29NH2 HAVING A MOLECULAR WEIGHT OF FROM ABOUT 185 TO ABOUT 213, A MIXTURE OF PRIMARY AMINES FROM T-C18H37NH2 TO T-C21H3NH2 HAVING A MOLECULAR WEIGHT OF ABOUT 269 TO ABOUT 311 AND N-BENZYLHEPTADECYLAMINE, SAID AMINE BEING DISSOLVED IN AN ORGANIC, WATER-IMMISCIBLE INERT SOLVENT IN A CONCENTRATION OF ABOUT 0.1 TO 0.5 MOLE PER LITER, TO FORM AN ORGANIC EXTRACT PHASE AND AN AQUEOUS RAFFINATE PHASE, WHEREBY AT LEAST ONE RARE EARTH ELEMENT IS SELECTIVELY TRANSFERRED AT LEAST IN PART TO THE EXTRACT PHASE, SEPARATING THE EXTRACT AND RAFFINATE PHASES, AND RECOVERING RARE EARTHS FROM SAID PHASES.

Claim 2

A METHOD FOR THE SEPARATION OF AT LEAST ONE RARE EARTH ELEMENT FROM AT LEAST ONE OTHER RARE EARTH ELEMENT IN AN AQUEOUS SULFATE SOLUTION CONTAINING THE RARE EARTHS IN A CONCENTRATION OF ABOUT 0.005 TO 0.05 MOL PER LITER WHICH COMPRISES (1) ADDING TO SAID SOLUTION ABOUT 2 TO 10 GRAMS PER LITER OF THE SOLUTION OF A COMPLEXING AGENT SELECTED FROM THE GROUP CONSISTING OF ETHYLENEDIAMINE TETRAACETIC ACID, DIETHYLENETRIAMINE PENTAACETIC ACID, NITRILOTRIACETIC ACID, 1, 2-DIAMINOCYCLOHEXANE TETRAACETIC ACID, N-HYDROXYETHYLENEDIAMINE TRIACETIC ACID AND A-ISOBUTYRATE, AND (2) CONTACTING SAID AQUEOUS SOLUTION WITH AN AMINE FROM THE GROUP CONSISTING OF A MIXTURE OF PRIMARY AMINES FROM T-C12H25NH2 TO T-C14H29NH2 HAVING A MOLECULAR WEIGHT OF FROM ABOUT 185 TO ABOUT 213, A MIXTURE OF PRIMARY AMINES FROM T-C18H37NH2 TO T-C21H3NH2 HAVING A MOLECULAR WEIGHT OF ABOUT 269 TO ABOUT 311 AND N-BENZYLHEPTADECYLAMINE, SAID AMINE BEING DISSOLVED IN AN ORGANIC, WATER-IMMISCIBLE INERT SOLVENT IN A CONCENTRATION OF ABOUT 0.1 TO 0.5 MOLE PER LITER, TO FORM AN ORGANIC EXTRACT PHASE AND AN AQUEOUS RAFFINATE PHASE, WHEREBY AT LEAST ONE RARE EARTH ELEMENT IS SELECTIVELY TRANSFERRED AT LEAST IN PART TO THE EXTRACT PHASE, SEPARATING THE EXTRACT AND RAFFINATE PHASES, AND RECOVERING RARE EARTHS FROM SAID PHASES.